Spliced leader trans-splicing is an essential RNA processing step that is required for the formation of mRNA in many eukaryotes, including C. elegans. However, the role of factors involved in this reaction is not well known. Here we further characterise the function of SNA-2, SNA-3, SUT-1 and SNR-2 involved in spliced leader 1 trans-splicing through identification of interacting proteins by immunoprecipitation followed by LC-MS/MS and label-free quantification.